Two men have died and four have been injured after a minibus carrying men involved in a heavy-metal band tour has crashed down an embankment of the Pacific Highway.

The minibus was in a convoy carrying "deathcore-metal" bands All Shall Perish and The Red Shore on their Christmas Carnage tour.

A spokeswoman for the tour organiser said that members of the California-based All Shall Perish were not involved in the crash. She was unable to provide details about the dead men.

The bands were due to perform at Hermann's bar at the University of Sydney tonight.

One man was pronounced dead at the crash site, while a second man died at Coffs Harbour hospital after being trapped for an hour in the minibus after the minibus veered off the road and rolled down an embankment near Cunninghams Bridge at Moonee Beach in northern NSW at 7am.

Four other male passengers are in a stable condition.

Police have closed the highway in both directions, and have urged motorists to avoid the area if possible.

"There will be local traffic diversions in place, but we are urging people to avoid the area if at all possible," a police spokesman said.

Another multiple vehicle accident on the Pacific Highway at Emerald Beach brought a large section of the road to a stand-still for nearly an hour this morning.

The second accident involved a pile-up of up to seven vehicles and happened at about 8am on Pacific Highway at Emerald Beach.

Police believe that one car was preparing to turn right when it was hit, causing a chain-reaction. A police spokeswoman said all the people involved had only minor injuries.

The northern direction of the highway is still closed, and police have urged motorists to avoid the area if possible.

The accidents comes just days after five people, including three generations of women from a Sydney family, were killed when their car collided with a truck on a northern NSW highway.

Heather Corcoran, aged 70, her two daughters, Lorraine Corcoran, 44, and Donna Corcoran, 47, and her 21-year-old granddaughter Melieta Corcoran all died in the crash, which occurred 10km north of Boggabri on Sunday.

The young woman's 22-year-old partner, identified in media reports as Brandon Jacobs of Penrith, also died in the accident.